The present invention relates to an endoscopic tissue collecting instrument suitable for use typically in a biopsy of the pancreas and the liver by being inserted into and removed from a treatment instrument insertion channel in an endoscope.
FIG. 10 shows the distal end portion of a Menghini needle used as an endoscopic tissue collecting instrument. It comprises a rod-shaped needle shaft 80 having a pointed end 81 and a tissue retaining recess 82 formed in the lateral side of an area close to the needle end 81 and into which an excised tissue specimen 101 is retained.
A cannula or outer sheath 90 is fitted over the needle shaft 80 to be capable of moving back and forth along the longitudinal axis and it has an annular blade 91 formed on the inner circumference of the distal end for cutting off the tissue retained in the recess 82.
Before passage into the treatment instrument insertion channel of an endoscope, the endoscopic tissue collecting instrument is passed through a guide tube (not shown) typically made of a tetrafluoroethylene resin to prevent the needle tip 81 from damaging the insertion channel.
A problem with the above-described endoscopic tissue collecting instrument is that the depth of the tissue retaining recess 82 is inevitably much smaller than the diameter of the outer sheath 90, often causing a failure to collect an adequate amount of the tissue specimen.
An object, therefore, of the present invention is to provide an endoscopic tissue collecting instrument with which an adequate amount of the tissue specimen can be easily collected without increasing the diameter of the outer sheath.
According to the present invention, the tissue accommodated in the outer sheath via a tissue retaining recess formed in its lateral side can be used as a specimen for biopsy. The collected tissue specimen has the largest size that can be expected from the given diameter of the outer sheath. Hence, an adequate amount of the tissue specimen can be easily collected without increasing the diameter of the outer sheath.
In addition, since an inner needle is simply slid within the outer sheath to cut off the tissue specimen, sliding resistance is small, and the cutting operation can be done efficiently. An endoscopic tissue collecting instrument of a preferred embodiment includes:
an outer sheath including:
an annular blade portion formed on an outer periphery of a distal end of the outer sheath to be directed forward; and
a tissue retaining recess formed in a lateral side of an area close to the blade portion; and
an inner needle that is fitted into the outer sheath to be capable of moving back and forth along a longitudinal axis, the inner needle including:
a cutting blade, formed at a distal end of the inner needle, for cutting off a tissue entering the tissue retaining recess; and
a needle tip formed at the distal end of the inner needle, and pointed forward, wherein:
the inner needle can be manipulated from an operator side to move back and forth between two positions, one being where the distal end of the inner needle is drawn into the outer sheath such that it does not close the tissue retaining recess and the other being where it protrudes from the distal end of the outer sheath.
The distal end of the inner needle may be in the form of a tube, and the cutting blade may be formed on an inner periphery of the tube. The endoscopic tissue collecting instrument may further include an aspiration channel that communicates with the tissue retaining recess at a distal end thereof and which extends to a basal end of the outer sheath. In this case, the aspiration channel may be formed in the inner needle, and a connection socket for establishing connection to an aspirating device may be provided at a basal end of the inner needle.
The tissue retaining recess may be a cutout formed in the lateral side of said outer sheath. The endoscopic tissue collecting instrument may further include a guide tube through which the outer sheath is passed to be capable of moving back and forth along the longitudinal axis. The needle tip of the inner needle may also serve as the cutting blade.
The present disclosure relates to the subject matter contained in Japanese patent application No. Hei. 11-336915 (filed on Nov. 29, 2000), which is expressly incorporated herein by reference in its entirety.